Letrozole Biogaran (Letrozole)

Letrozole is an aromatase inhibitor used in the treatment of breast cancer that depends on estrogen signaling.

• Hormone receptor‑positive breast cancer (postmenopausal): reduces estrogen production to slow tumor growth.
• Adjuvant therapy for early‑stage breast cancer (postmenopausal): helps prevent recurrence after surgery.
• Metastatic breast cancer (postmenopausal): improves progression‑free survival.

• Letrozole reversibly binds to the aromatase enzyme, a non‑steroidal inhibition that blocks the conversion of androgens to estrogens. By decreasing systemic estrogen levels, it deprives estrogen‑dependent tumor cells of a growth stimulus, thereby limiting proliferation of hormone‑sensitive breast cancer cells.

Letrozole may cause a range of adverse reactions, from mild to serious.

Common Side Effects

• Hot flashes: sudden feeling of warmth and sweating.
• Joint or muscle pain: aching in limbs or back.
• Fatigue: persistent tiredness not relieved by rest.
• Nausea: upset stomach, sometimes with vomiting.
• Headache: mild to moderate intensity.
• Dizziness: light‑headed sensation, especially when standing.

Serious or Rare Side Effects

• Severe bone loss or osteoporosis: increased fracture risk.
• Liver function abnormalities: elevated enzymes indicating hepatic stress.
• Cardiovascular events: hypertension, thromboembolic episodes.
• Severe allergic reactions: rash, swelling, breathing difficulty.
• Elevated cholesterol levels: may worsen lipid profile.
• Bone pain with possible fractures: persistent skeletal discomfort.

Before initiating Letrozole therapy, several safety considerations are recommended.

• Bone health monitoring: assess bone mineral density regularly.
• Liver function assessment: perform baseline and periodic liver enzyme tests.
• Cardiovascular risk evaluation: review history of hypertension or clotting disorders.
• Avoid use in premenopausal women: drug is ineffective without postmenopausal estrogen status.
• Review concomitant medications: check for interactions that may alter letrozole levels.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Letrozole can interact with other medicines, affecting its efficacy or safety.

Major Interactions (Avoid)

• Strong CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce letrozole exposure.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may increase letrozole concentrations.
• Estrogen replacement therapy: counteracts letrozole’s estrogen‑lowering effect.

Moderate Interactions (Monitor Closely)

• Warfarin: letrozole may alter INR, requiring closer coagulation monitoring.
• Statins: potential additive effect on liver enzymes, monitor hepatic function.
• Selective serotonin reuptake inhibitors (SSRIs): may influence hormone metabolism, observe for side‑effect changes.